What is the maximum/minimum pressure/temperature at which Danfoss switches can be set?
Answer: Danfoss manufactures various pressure switches which can have a setting range of anywhere between -1 to 400 bar and temperature switches from -60 to +300°C.
However, each switch will have its own regulation range as detailed within the product catalogue pages. It is always good practice to avoid choosing a product which will be switching near to the limits of its range.
What is the DIN numbering of terminals?
Answer: Terminal numbers are always ODD for inputs & EVEN for outputs, which explains why the changeover switch in almost all pressure & temperature switches has numbers 1, 2 & 4. The live feed goes in at 1. It comes out at 2 when the pressure or temperature is low (so take this to your pump or heater as a live feed) out of 4 when the temperature or pressure is high. (You can take terminal 4 to a ''satisfied'' tell-tale lamp or to an unloading valve or cooling fan, if you wish).
How can I characterize vapour charge in the sensor of the temperature switch?
How I can characterize adsorption charge in the sensor of the temperature switch?
Answer: The sensor is partially filled with carbon particles, and the rest of the element contains superheated gas, normally CO2. Reaction is always in the sensor and working point will vary with the ambient temperature.
After installing the switch and making the setting based on scale values, the real system pressure value and scale value seem not to correspond. What is the reason?
What is the time constant in relation to temperature switches?
I am looking for the on/off switch with the highest possible IP protection, what options do I have?
How does the manual reset work in relation to on/off switches?
What does SPDT stands for?
What is the most common contact system type used in Danfoss switches?
Is it possible to improve the IP enclosure grade for KP switches?
What would be the best pressure switch choice for applications requiring high repeatability, accuracy and adjustable differential?
When is it recommended to use a gold-plated contact system?
How can I improve the heat transfer if I use a sensor pocket with a temperature switch?
Where I can find technical information regarding on/off switches?
Is it possible to change the set point in a pre-set KP temperature switch, e.g. from 35°C to 29°C?
How many cycles can KP switches perform?
Answer: Units are taken from current production for life tests, electrical and mechanical. The tests are carried out under the most severe conditions. The mechanical life time test has to fulfill at least 400,000 cycles – the average is 1,000,000 cycles. The electrical life time test has to fulfill at least 100,000 cycles (under full load) – the average is 400,000 cycles.
Why is there no information regarding scale correction in the technical brochure for a KP temperature switch?
Answer: Because the ambient temperature influence depends on 2 factors: 1) size of a sensor and length of the capillary tube, and 2) value of the ambient temperature.
KP switches usually have smaller sensors than KPS switches, and they are installed in less severe conditions than KPS, so ambient temperature influence is very small and could be omitted.
Is there any way to tell if charge is lost in a temperature switch?
I am looking for a KP temperature switch for a small load: 10mA at 110V dc. Is it preferable to use gold contacts for this application?
Answer: Although amperage is quite low, standard silver contacts can be used because the voltage is high enough. If in doubt, the gold-plated contacts can be used. In cases where the load is too high, the golden layer will be burnt away and silver contacts will remain.
A diagram showing when gold plated contacts shall be used is available in the technical brochure, downloadable from our internet catalogue.
Do Danfoss temperature switches come with sensor pocket included?
How do I maximize response time of a temperature switch?
Answer: First, the sensor should be immersed in the media with biggest possible surface. If this is not possible and a sensor pocket is needed, remember that the additional thermal inertia of the pocket will play a significant role. You can use heat conductive paste to reduce it.
What do I do if I need very quick reaction to changing temperature?
Answer: In case of any mechanical switch with charge sensor, the reaction time will always be a considerable factor. The solution could be using a temperature sensor, which has much smaller themal inertia.
What is the response time of Danfoss temperature switches?
Answer: There is no exact data on the time constant for temperature switches in particular - it largely depends on sensor charge, way of mounting (contact to media), temperature changing speed, ambient temperature and other factors.
Which temperature switch should I use to control the area temperature in an engine room?
Which switches should I use for seawater - or other media with particles or depositions?
Answer: In case of seawater you should generally use diaphragm versions of switches:
- KPS 43, 45 & 47
- CAS 143, 145 & 147
- MBC 5100 with diaphragms
Seawater may contain contamination and certainly salt, both of which will likely accumulate inside the application. Not least inside the switch,, because the water inside is almost still (no flow). If salt crystallizes on the bellows surface it can easily affect its proper function.
In case of diaphragms, very smooth and flexible, this problem is less visible. This will cause the depositions to be removed from its surface, and until the whole system is filled and blocked with depositions, it will work.
Depositions are especially dangerous when you have a small bellows - like in MBCs.
If you need to use bellows version of switches then try to choose comparatively big bellows - surfaces on which depositions are stored are comparatively far away and it would take a longer time before they affect bellows function. RT is a switch of this kind.
Where do I find production date on pressure or temperature switches?